The Great Planetary Conjunc...

Over the next two months we will be treated to a spectacular planetary conjunction. This dance will occur in the glow of sunset and will involve four bright planets and on a few nights, the Moon as well. Even now the dancers are orbiting towards their rendezvous. The diva of this show will be the bright planet Venus, she will be accompanied by the leading man, Saturn. Mars and Mercury round out the planetary cast, the only bright planet conspicuously absent will be Jupiter.

If you get out to take a look tonight, you may spy Mercury just beginning to escape the Sun's glare, low on the horizon in the fading glow. The other planets form a line along the ecliptic 75° east of the Sun which sets at 7pm. This line will contract as the dancers assume their places and the show begins.

A particularly nice sequence of days will start July 12, when a razor thin crescent Moon will join for a pass through the group. on the 12th it will be quite low, just 5° south of Mercury. Two days later a thicker but still beautiful Moon will be paired with Venus. The next day the Moon will be closer to Saturn and Mars.

The dance climaxes on the evening of August 12th when a beautiful crescent Moon joins the show. This evening will feature five naked eye solar system objects within 22° of each other. This is the night you find an appropriately scenic western horizon, maybe with a palm tree or observatory dome, and take the perfect photograph. The night is also the peak of the annual Perseid meteor shower, making for a great night to get out and observe.

Towards the end of August Mercury will exit stage east, leaving only three planets on the platform. As September progresses there will still be a few more nice trios and pairs occurring, but the main show will be over.

Any evening through the next two months will provide a show as these planets gather in the sunset. Keep your browser or RSS reader pointed to Darker View for a step by step guide to the Great Planetary Conjunction of 2010.